I never use and, or, and not for putting together "logical expressions"1(!$b || $c && $d), but always use the higher precedence C-style operators. The only time I use the three letter ones is when "englishing" an expression do {expression} or die. If it is a formula, use the C-style operators, if it is English, use the words.

I probably made that as clear as mud.

1 Yeah, I know both of these are logical expressions, I could not find the English words with enough meaning and distinction to clarify the difference.

Update: What jplindstrom said in the next subthread is spot on to what I tried to say here.